Question

How many terms are there in the A.P.?
(i)7,10,13,...43
(ii)-1,-5/6,-2/3,-1/2,...,10/3
(iii)7,13,19,...,205.
(iv)18,15 1/2,13,...,-47

Answer 1

Answer:

18,15 1/2,13,...,-47 is a write answers

Answer 2

(i) 12 terms

(ii)  26 terms

(iii) 33 terms

(iv) 26 terms

Step-by-step explanation:

(i)7,10,13,...43

d = 3

a = 7

an = 43

an = a +nd

So we get 7 +3n = 43

 3n = 43 - 7

 3n = 36

 Therefore n = 36/3 = 12.

There are 12 terms in this AP.

(ii)-1,-5/6,-2/3,-1/2,...,10/3

d = -5/6 + 1 = -5+6/6 = +1/6

an = a + nd = 10/3

 -1 + n/6 = 10/3

 n/6 = 10/3 + 1

 n = 13/3 * 6

 n = 26

(iii)7,13,19,...,205.

d = 6

 an = a + nd = 205

  205 = 7 + 6n

  6n = 205 - 7

  n = 198/6

  n = 33

(iv)18,15 1/2,13,...,-47

d = -5/2

an = a + nd = -47

 -47 = 18 -5n/2

 5n/2 = 18 +47

   n = 2 * 65/5

   n = 26